Additionally, a replacement of the second intron with other introns in the beta-globin gene in human led to a reduction of the efficiency of 3'-end formation [64]. Introns, particularly first introns, have important roles in the correct cytoplasmic localization of some mRNAs, including the Drosophila oskar gene and mRNA export [6065] as well as in transcriptional and translational regulation [616667].
